In a Post a few months ago, I described how a beaver family took up residence on Lake Walter and doubled the depth of the lake, read it here.
Lake Walter Dam failed catastrophically between 3 pm and 4:15 pm EDT on 10/8/16, after we got 14″ of rain in 18 hours from Hurricane Matthew. This came after the area got 8″ of rain from Tropical Storm Julia just 9 days prior.
Photos taken before and after the breach follow.
——————————————————————————
Taken 10/8/16, 2:58 pm edt
Standing in moderate rain in about a foot of moving water (about all I could safely stand in for an extended interval) on the north edge of Lake Club Drive, facing north. The hydraulic reversal has already migrated upstream through a pile of construction debris placed below the dam several years ago by the PWC to mitigate erosion.The reversal is now rapidly cutting upstream through soil. I called 911 after returning home. They took 5 minutes to answer. No indication that law enforcement responded. I then knocked on the doors of my neighbors with houses near creek level to share the news of this threat.
Something you see routinely on the mountain streams – but rarely seen in the Sandhills!
——————————————————————————
A neighbor obtained video footage at 4:15 that showed a complete breach.
——————————————————————————
Taken 10/8/16, 5:33 pm
Standing on the edge of nearly dry pavement east of the fully breached dam. The former continuation of the road is apparent on the other side.
The hydraulic reversal is now just upstream of what was until perhaps an hour ago, the lakeside bank of the dam.
I think that the water colored yellow with mud on the left is coming from the tributary to Blounts Creek that comes into the lake just above the dam (from Coffman St., and then through a tunnel under the CSX railway) – probably because of the housing development now taking place at the west end of Coffman.
——————————————————————————
I was eating noodles on the second floor of my house without electrical power, looking through a window, monitoring the creek level on my back fence, when I expect the breach happened. I observed the creek level drop monotonically from a crest at about 3 pm – well before the breach! I think that we were spared a deluge because the lake was largely empty when the final breach occurred.
——————————————————————————
It wasn’t the fault of the beavers – I think their modifications played no role in this dam failure.
Taken 10/9/16, ~10 am. The erosion moved only a few feet upstream from where it was yesterday at 5:33 pm.
——————————————————————————
The new spillway – photographed on 10/10/16, now stable, until we get substantial rain, when erosion can be expected to proceed upstream into the lake.
——————————————————————————
Maintaining Lake Walter to Mutual Advantage
I suggest that we seriously consider living intentionally with the Beaver. Vigilant human over site will be needed. The current breach site might provide a great opportunity to construct a robust spillway. Perhaps a $1000 cement block structure. This structure would be designed to also breach completely away in the event of extreme rainfall. But it will provide for the clearing of clogged logs from its downstream ramparts. It will be built with the expectation that our Beaver friends will maintain a soft overstructure that will increase the lake level approximately 1.5 feet above the block level.
An existing drain to the west of the spillway could also assist in the assurance of an appropriate lake level.
——————————————————————————
Wild life photographed on 10/12/16.
Canadian Geese feeding on whats left of Lake Walter. An Egret with spread wings sitting in the top of a tree on the left.
——————————————————————————
On 10/9, I attempted to kayak from Lake Walter to the Cape Fear. However, due to the fallen trees in the water at this rapid – let me call it Matthew’s Deluge – I could not see any plausible kayaking line through it. I put in instead ~1.5 km downstream at Whitfield St. My account is here.
John Mattox
Last modified, 10/12/16